FIG. 1 illustrates a relay node (RN) 120 and user equipments (UE) 131 and 132, which exist within one base station (eNodeB; eNB) 110 in a wireless communication system 100. The relay node 120 may forward data received from the base station 110 to the user equipment 132 therein and forward the data received from the user equipment 132 therein to the base station 110. Also, the relay node 120 may extend a high data rate region, enhance communication quality at a cell edge, and support communication inside a building or a zone beyond base station service coverage. In FIG. 1, a user equipment (hereinafter, referred to as macro-user equipment (Macro-UE or M-UE)) such as the user equipment 131, which directly receives a service from the base station, and a user equipment (hereinafter, referred to as relay-user equipment (Relay-UE or R-UE)) such as the user equipment 132, which receives a service from the relay node 120, are shown.
A wireless link between the base station 110 and the relay node 120 will be referred to as a backhaul link, a link from the base station 110 to the relay node 120 will be referred to as a backhaul downlink, and a link from the relay node 120 to the base station 110 will be referred to as a backhaul uplink. Also, a wireless link between the relay node 120 and the user equipment 132 will be referred to as an access link. A link from the relay node 120 to the user equipment 132 will be referred to as an access downlink, and a link from the user equipment 132 to the relay node 120 will be referred to as an access uplink.
Furthermore, in the case that the relay node 120 is operated in such a way to control a cell by itself, the user equipment 132 may recognize the relay node 120 as a normal base station.